Brightness varies depending on the environment in which the user uses a display device. In an environment in which external light is bright, external light irradiating on the display screen of the display device degrades the visibility of the original image.
Patent Literature 1 discloses an image processor including a gain derivation unit that derives a compression gain to be applied to the low-frequency component of an input image and an enlargement gain to be applied to the high-frequency component of the input image from illuminance acquired from an illuminance detector and a display image generator that generates a display image where the pixel value of the input image has been corrected, on the basis of the compression gain and enlargement gain derived by the gain derivation unit.